Esophageal balloon catheter with asymmetrical balloon

ABSTRACT

A balloon catheter for use with an endoscope may have a flexible shaft extending between a proximal and distal end, with a hub affixed to the proximal end, and a balloon that is longitudinally asymmetrical. A balloon may have a central or cylindrical working portion, flanked by proximal and distal tapering portions, which are in turn flanked by proximal and distal balloon legs, which are affixed to the catheter shaft. In more specific detail, a longitudinally asymmetrical balloon may have proximal and distal tapering portions that have a relatively steep and a relatively shallow tapering angle, respectively. An optional additional feature of such a balloon catheter is that the catheter shaft may have a high pull strength and low longitudinal elongation, by including some type of reinforcement.

BACKGROUND AND SUMMARY OF THE INVENTION

1. Technical Background

The present invention relates generally to medical devices, and moreparticularly to a balloon catheter for use with an endoscope.

2. Discussion

There are many different kinds and types of balloon catheters, includingfor example angioplasty catheters, stent delivery system catheters, etc.

By way of example, the present invention will be described in relationto an esophageal balloon catheter. However, it should be understood thatthe present invention relates to any balloon catheter having thefeatures recited in any one of the following claims, and is not limitedto any particular treatment such as esophageal use, or use with anendoscope, or the particular example embodiments described below.

Balloon catheters often have a relatively flexible tubular shaft havinga certain length, which defines one or more tubular passages or “lumens”extending through part or all of the catheter shaft, and has aninflatable balloon attached near one end of the shaft. This end of thecatheter where the balloon is located is customarily referred to as the“distal” end, while the other end is called the “proximal” end. Theproximal end of the shaft is generally coupled to a hub, which definesan inflation port for connection to an inflator for selectively applyingpressure to a fluid inflation medium, thus inflating the balloon.Structurally, the inflation port leads to an inflation lumen defined bythe shaft, which extends to and communicates with the interior of theballoon, for the purpose of selectively inflating and deflating theballoon.

When a catheter includes a lumen adapted to slidingly receive aguidewire, it is referred to as a “guidewire lumen,” and it willgenerally have a proximal and distal “guidewire port.” The distalguidewire port is often at or near the catheter shaft distal end.

A guidewire has a flexible wire-like structure extending from a proximalend to a distal end. The guidewire will usually be of a size selected tofit into and slide within a corresponding guidewire lumen of a catheter.

If a balloon catheter includes a hub affixed to the catheter shaftproximal end, the hub may serve a variety of functions. Such functionsmay include providing a handle for manipulating the catheter, and/ordefining proximal port(s) communicating with lumen(s) defined by thecatheter shaft. When there is a guidewire lumen defined by a cathetershaft, its proximal guidewire port may be defined by a proximal hub,referred to as an “over-the-wire” catheter; or the proximal guidewireport may be located at some point along the sidewall of the cathetershaft, referred to as a “rapid exchange” catheter.

When a catheter has no guidewire lumen, but instead has a flexible wireor wire-like distal extension affixed to the catheter, it may bereferred to as a “fixed wire” catheter. Whether a particular catheterhas a guidewire lumen or has a fixed-wire design, the guidewire orfixed-wire is intended to allow the catheter to more easily select andsteer along a desired path.

In a fixed wire balloon catheter, a wire or wire-like structure maysimply be attached to the distal end of the balloon catheter.Alternately, a flexible wire or wire-like structure may be affixed tothe proximal hub, extending from the proximal end of the catheter,though the shaft and the balloon (perhaps in a dedicated lumen), and mayextend a relatively short distance distal of the balloon. In anotherpossible configuration, a distal extension of an inner body of thecatheter shaft may serve as a “fixed wire” guiding element.

In general, balloon catheters according to the present invention mayhave one or more of the following features: (i) a balloon that islongitudinally asymmetrical; and/or (ii) a catheter shaft having a highpull strength.

In greater detail, an asymmetrical balloon may have a cylindricalworking portion, flanked by proximal and distal tapering portions, whichare in turn flanked by proximal and distal balloon legs, which areaffixed to the catheter shaft. A possible feature of a longitudinallyasymmetrical balloon is having proximal and distal tapering portionsthat taper at different angles.

In the case of a balloon catheter for use with an endoscope, the balloonmaterial may be translucent, to allow a physician to use the endoscopeto look through the balloon material at the anatomy, so the physiciancan accurately position the balloon. In addition, the proximal taperingportion of a translucent balloon may have a relatively steep taperingangle, to enhance the clarity of the picture presented to the physicianby the endoscope.

Again in the case of a balloon catheter for use with an endoscope, afteror during a therapeutic procedure, a physician may wish to retract theballoon catheter back into a passage or lumen defined by the endoscope.Another example may be a balloon catheter for use with a guidingcatheter which defines a lumen. During such retraction into an endoscopeor guiding catheter, the balloon material of some balloon catheters maypossibly “bunch up” toward the distal direction as the balloon catheteris withdrawn back into such a passage or lumen, which may makeretraction difficult.

Accordingly, another possible feature of a balloon catheter may be aballoon having a distal tapering portion with a relatively shallowtapering angle, so as to facilitate retraction of the balloon catheterback into an endoscope. The resulting gradual change in distal balloonsize may tend to cause the balloon material to more easily fold or pleatand reenter a passage defined by the endoscope, thus reducing retractionforce.

Regarding high pull strength, it may be desirable to provide a cathetershaft of a balloon catheter with reinforcement, such as reinforcingbraid or strand(s). The resulting stronger catheter shaft will thusexhibit low longitudinal elongation under stress. Accordingly, ifretraction becomes difficult, such reinforcing element(s) will tend toresist elongation of the catheter shaft.

An optional additional feature may be one or more visual markersprovided on the balloon material or in the balloon material itself. Suchvisual markers may assist a physician to accurately position theballoon. In the case where a balloon catheter is used with an endoscope,the marker may be viewed visually with the endoscope, by using theendoscopic lens to look through the balloon material of the proximaltapering portion. In other words, the physician's view is provided by anendoscope positioned proximal of the balloon, yet the physician can lookthrough the translucent material of the balloon proximal taperingportion, and see the interior surface of a cylindrical working portionto visualize where the marker(s) is from the “inside.”

Such a visual marker may have any suitable shape or arrangement,including a circumferential band placed at the longitudinal center ofthe balloon, or a marker placed at one or both of the transitionsbetween a central working portion and the proximal and distal taperingportions. Such markers may enable a physician to use the view through anendoscope to accurately position the balloon at the desired site fortreatment, for example centered within a lesion or stricture. Of course,various combinations of these marker arrangements may be used.

In another optional additional feature, the marker(s) may becolor-coded. For example, a marker of a particular color may indicatecertain properties, such that the catheter balloon is of a particularsize, allowing a physician to quickly confirm that the desired sizeballoon has been selected for use. Visual markers may also be made ofdifferent sizes or patterns, to indicate balloon catheter properties.

This disclosure of the present invention will include various possiblefeatures and embodiments. However, the present invention scope as setforth in each of the claims, and is not limited to the particulararrangements described in this disclosure.

The terms “tube” and “tubular” are used in their broadest sense, toencompass any structure arranged at a radial distance around alongitudinal axis. Accordingly, the terms “tube” and “tubular” includeany structure that (i) is cylindrical or not, such as for example anelliptical or polygonal cross-section, or any other regular or irregularcross-section; (ii) has a different or changing cross-section along itslength; (iii) is arranged around a straight, curving, bent ordiscontinuous longitudinal axis; (iv) has an imperforate surface, or aperiodic or other perforate, irregular or gapped surface orcross-section; (v) is spaced uniformly or irregularly, including beingspaced varying radial distances from the longitudinal axis; or (vi) hasany desired combination of length or cross-sectional size.

Any suitable material may be used to make the components described,including polymers, metals and other materials suitable for use withmedical devices.

It is of course possible to build various kinds and designs of cathetersaccording to the present invention, by various techniques and of variousmaterials, to obtain the desired features. It should be noted that thepresent invention also relates to methods for making and using a ballooncatheter, in addition to the balloon catheter itself.

These and various other objects, advantages and features of theinvention will become apparent from the following description andclaims, when considered in conjunction with the appended drawings. Theinvention will be explained in greater detail below with reference tothe attached drawings of a number of examples of embodiments of thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a balloon catheter;

FIG. 2 is a perspective view of a balloon catheter with visual markers;

FIG. 3 is a longitudinal cross-section view of a balloon catheter;

FIG. 4 is a longitudinal cross-section view of a balloon catheter; and

FIG. 5 is a transverse cross-section view of the balloon catheter ofFIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiments of the presentinvention is merely illustrative in nature, and as such it does notlimit in any way the present invention, its application, or uses.Numerous modifications may be made by those skilled in the art withoutdeparting from the true spirit and scope of the invention.

The drawings depict a variety of balloon catheters and various features.FIG. 1 shows a balloon catheter 10 having a balloon 12, a flexible shaft14, and a hub 16. The shaft 14 has a proximal and distal end, with theballoon 12 being attached to the shaft 14 near the distal end, and thehub 16 attached to the shaft 14 near the proximal end. A distal tipelement 18 is affixed to the shaft 14 at the distal end, and a strainrelief 20 is positioned at a transition between the shaft 14 and the hub16. Balloon 12 has a cylindrical working portion 22, flanked by aproximal and distal tapering portion 24 and 26, which are in turnflanked by a proximal and distal balloon leg 28 and 30.

The balloon catheter 32 shown in FIG. 2 is similar to balloon catheter10 in FIG. 1, with a balloon 34, a flexible shaft 36, a hub 38, a distaltip element 40, and a strain relief 42. In addition, balloon catheter 32has some visual markers on the material of the balloon 34.

In the specific example shown in FIG. 2, the balloon 34 has a centralmarker 44 that encircles the longitudinal center of the balloon, as wellas a pair of markers 46 and 48 which indicate the proximal and distalextent of a working portion of the balloon. The visual markers may be ofvarious sizes, colors, and arrangements. In the example shown in FIG. 2,markers 46 and 48 are wider than central marker 44. In one possibleexample, markers 46 and 48 may be spaced approximately 2.5cm from thecentral marker 44.

FIG. 3 shows a balloon catheter 50 having a balloon 52, a flexible shaft54, and a hub 56. The shaft 54 has a proximal and distal end, with theballoon 52 being attached to the shaft 54 near the distal end, and thehub 56 attached to the shaft 54 near the proximal end. The hub 56defines an inflation port in fluid communication with an inflation lumendefined by the shaft. A distal tip element 58 is affixed to the shaft 54at the distal end, and a strain relief 60 is positioned at a transitionbetween the shaft 54 and the hub 56. Balloon 52 has a cylindricalworking portion 62, flanked by a proximal and distal tapering portion 64and 66, which are in turn flanked by a proximal and distal balloon leg68 and 70.

In the illustrated example, the proximal and distal tapering portions 64taper at different angles, with the proximal tapering portion 64tapering at a much steeper angle than distal tapering portion. Forexample, one arrangement of a balloon catheter may include a shallowdistal tapering angle of approximately 45 or 50 degrees with respect toa longitudinal axis, while the proximal tapering angle may be as closeto perpendicular as possible, for example within approximately 10degrees of perpendicular.

The flexible shaft 54 of FIG. 3 includes an inner member 72 and an outertubular body 74. Inner member 72 extends from the hub 56 to the distaltip element 58, and may have high pull strength to serve as areinforcing wire. The resulting stronger catheter shaft will thusexhibit low longitudinal elongation under stress. The proximal anddistal ends of inner member 72 may be affixed to the hub 56 to thedistal tip element 58 by any suitable means, including heat sealing,injection molding, and an adhesive. Of course, inner member 72 may bemade of various materials having the desired properties, includingstainless steel.

FIGS. 4 and 5 show partially diagrammatic views of a balloon catheter 76having a similar arrangement, including a balloon 78, a flexible shaft80, and a hub 82. The shaft 80 in this example has an inner member orstiffening wire 84, and a tubular outer body 86. Outer body 86 also hasan integral wire 88 extending within the wall of outer body 86, whichmay be stainless steel or another material having high pull strength andlow elongation under stress.

Balloon catheters according to the principles of the present inventionmay be made of any suitable material using a variety of methods. Variouspolymers have the desired characteristics of strength, resilience,flexibility, biocompatibility and endurance. Many different materialsmay be used for manufacturing steerable catheters of the presentinvention. For example, some of the polymer materials may includepolyamides, polyurethanes, nylons, polyethylenes, including high-densitypolyethylene (HDPE), polyether block amide (PEBA) which is available asPebax®, polyester (PET), polycarbonate, polypropylene,acrylonitrile-butadiene styrene terpolymer (ABS), orpolyetheretherketone (PEEK). Also, any of the catheter components may bemade of a co-extrusion or a blend or a block copolymer of such polymermaterials.

Many variations on components and designs of a balloon catheter arepossible. For example, a reinforcing element may be included usinganother material, such as Kevlar or Dyneema (HDPE) fibers. Alternately,reinforcing member(s) may be embedded in the wall of the outer body, andmay include a single wire or fiber, or may include multiple fibers whichmay be braided or coiled about the outer body.

EXAMPLE

An example balloon catheter may be constructed, including a nylonballoon, nylon tubular outer body, a stainless steel inner member and astainless steel wire embedded in the wall of the outer body. The wiremay for example have a diameter of 0.2 mm, which can reduce elongationof the shaft to less than 1 mm per meter of catheter length, when a pullforce of about 20 N is exerted.

It should be understood that an unlimited number of configurations forthe present invention could be realized. The foregoing discussiondescribes merely exemplary embodiments illustrating the principles ofthe present invention, the scope of which is recited in the followingclaims. Those skilled in the art will readily recognize from thedescription, claims, and drawings that numerous changes andmodifications can be made without departing from the spirit and scope ofthe invention.

1. A balloon catheter for use with an endoscope, comprising: a flexibleshaft having a proximal end and a distal end; the shaft having an innermember and an outer tubular body; the outer body surrounding at least aportion of to inner member and defining an inflation lumen, the outerhaving at least reinforcing member; a balloon defining an interior andbeing made of translucent balloon material which is substantiallyinelastic; the balloon having an inflatable portion extending between aproximal and distal balloon portion, each proximal and distal balloonportion being affixed to the catheter shaft; wherein the balloon isaffixed to the catheter shaft near its distal end; and the inflatableportion includes a cylindrical working portion arranged between aproximal and distal tapering portion; the balloon in an initialconfiguration being deflated, pleated and wrapped around the cathetershaft; a hub affixed to the proximal end of the shaft and defining atleast an inflation port; such that the inflation lumen communicatesbetween the hub and the balloon; wherein the proximal and distaltapering portions each define an angle with respect to the longitudinalaxis, and the angle defined by the proximal tapering portion is steeperthan the angle defined by the distal tapering portion.
 2. The ballooncatheter of claim 1, wherein the inner member is a wire having proximaland distal ends, the inner member distal end being affixed to theballoon distal portion, and the inner member proximal end being affixedto the hub.
 3. (canceled)
 4. The balloon catheter of claim 3, whereinthe reinforcing member has high tensile strength.
 5. The ballooncatheter of claim 3, wherein the reinforcing member is a Kevlar orDyneema fiber embedded within a wall of the outer body.
 6. The ballooncatheter of claim 3, wherein the reinforcing member is a stainless steelwire affixed to or embedded within a wall of the outer body.
 7. Theballoon catheter of claim 1, wherein the angle defined by the angledefined by the distal tapering portion with respect to the longitudinalaxis is approximately 45 degrees, and the angle defined by the proximaltapering portion is approximately 10 degrees from perpendicular.
 8. Theballoon catheter of claim 1, wherein the balloon further comprises atleast one visual marker.
 9. A balloon catheter for use with anendoscope, comprising: a flexible shaft having a proximal end and adistal end; the shaft having an inner member and an outer tubular body;the outer body surrounding at least a portion of the inner member anddefining an inflation lumen; at least one reinforcing member beingaffixed to the outer body for increasing tensile strength; a balloondefining an interior and being made of translucent balloon materialwhich is substantially inelastic; the balloon having an inflatableportion extending between a proximal and distal balloon portion, eachproximal and distal balloon portion being affixed to the catheter shaft;wherein the balloon is affixed to the catheter shaft near its distalend; and the inflatable portion includes a cylindrical working portionarranged between a proximal and distal tapering portion; the balloon inan initial configuration being deflated, pleated and wrapped around thecatheter shaft; a hub affixed to the proximal end of the Shaft anddefining at least an inflation port; such that the inflation lumencommunicates between the hub and the balloon; wherein the proximal anddistal tapering portions each define an angle with respect to thelongitudinal axis, and the angle defined by the proximal taperingportion is steeper than the angle defined by the distal taperingportion.
 10. The balloon catheter of claim 9, wherein the inner memberis a wire having proximal and distal ends, the inner member distal endbeing affixed to the balloon distal portion, and the inner memberproximal end being affixed to the hub.
 11. The balloon catheter of claim9, wherein the reinforcing member is a Kevlar or Dyneema fiber embeddedwithin a wall of the outer body.
 12. The balloon catheter of claim 9,wherein the reinforcing member is a stainless steel wire affixed to orembedded within a wall of the outer body.